1. Field of the Invention
The present invention relates to an array type light-receiving device and a hyperspectral spectrometer including the array type light-receiving device.
2. Description of the Related Art
Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2013-93385) discloses light-receiving devices and related techniques. The light-receiving device described in Patent Literature 1 has a plurality of pixels disposed on a semiconductor substrate. Each of the pixels of the light-receiving device includes a light-receiving layer for receiving light, a p-n junction disposed in the light-receiving layer, and a mesa structure defined by grooves. The plurality of pixels is spaced apart from each other by the grooves disposed around the mesa structures. An impurity wall layer is disposed on a wall surface of the mesa structure so as to prevent the p-n junction from being exposed at the wall surface of the mesa structure. Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2013-201219) discloses light-receiving devices and related techniques. The light-receiving device described in Patent Literature 2 has a plurality of pixels disposed on a semiconductor substrate. Each of the pixels includes a mesa structure defined by a groove. The mesa structure includes a light-receiving layer disposed in a stacked semiconductor layer, and a p-n junction located at an interface between the light-receiving layer and a p-type semiconductor layer disposed on the light-receiving layer. The plurality of pixels is separated from each other by the grooves disposed between the mesa structures. The groove is extended from a surface of the stacked semiconductor layer toward the semiconductor substrate through the p-n junction. The sidewall of the mesa structure is tapered such that the sectional area of the light-receiving layer is decreased toward the p-n junction. The semiconductor layer disposed on the light-receiving layer has an overhang portion that surrounds the p-n junction. The overhang portion of the semiconductor layer is overhung toward the grooves defining the mesa structure. Non-Patent Literature 1 (“MOVPE grown InGaAs/GaAsSb Type II Quantum Well Photodiode for SWIR Focal Plane Array”, H. Inada, H. Mori, Y. Nagai, Y. Iguchi, T. Saitoh, K. Fujii, T. Ishizuka, K. Akita, Proceeding of SPIE, vol. 8012 801220 (2011)) discloses a technique related to photodiodes having a type-II InGaAs/GaAsSb quantum well structure. Non-Patent Literature 1 describes a pixel size with a pixel pitch of 30 μm and a diameter of 15 μm.